I would start by buying some basics you really love and going from there...
So a really nice jacket, suede, leather etc. Something that will make any outfit look better...try Mango, COS, Whistles, John Lewis.
Then some jeans, you don't have to spend loads on these, but they should be durable. Since you're quite short I would go mid/high rise, straight leg, so you can wear them with anything. Black is probably smarter than blue. Levi's will get a perfect fit.
Then a smart but lovely dress in a colour you love. Finery? Warehouse? Something you could wear to work but also out?
Then I would buy some everyday tops, maybe in nicer fabrics so they could be smarter as well. Fat face or Gap, or Zara.
Maybe draw up a rough list, and don't feel you have to get everything in one if you're not seeing things you love.
Enjoy! I'm jealous!